1. Statement of the Technical Field
The present invention relates to private Personal Radio Services (PRS) for short distance two-way voice communications and more particularly to a location-based PRS device and apparatus.
2. Description of the Related Art
Personal Radio Services (PRS) include those short-distance two-way radio frequency voice communications services which can be used by individuals to communicate with others while in close proximity to one another. Historically, PRS included the Citizens Band (CB) Radio Service and the General Mobile Radio Service (GMRS). While both are regulated by the Federal Communications Commission (FCC), only the use of GMRS requires an operator license. With the CB Radio Service, users can expect a communications range of one to five miles. By comparison, with the GMRS, users can expect a range of five to twenty-five miles.
Recently, the FCC has authorized the use of the Family Radio Service (FRS). The FRS is a citizens band radio service which includes fourteen channels which can be used by individuals on a “take turns” basis. No FRS channel is assigned to any specific individual or organization. Rather, FRS is intended for use by civilians who can communicate among themselves within neighborhoods and while on group outings. Additionally, while it is not permissible to link an FRS device to the public switched telephone network, civilians may use an FRS device to conduct business-related communications. Presently, the FCC regulates the use of the frequency spectrum allocated to FRS devices and has published four rules pertaining to the operation of FRS devices in the United States Code of Federal Regulations, Title 47, Telecommunications, Part 80 to End.
Unlike FRS, Global Positioning System (GPS) devices have been publically available for nearly a decade. In fact, though GPS initially had been designed for and operated by the U.S. military, today there are many thousands of civilian users of GPS worldwide. In operation, GPS provides specially coded satellite signals that can be processed in a GPS receiver, enabling the receiver to compute position, velocity and time. Four GPS satellite signals are used to compute positions in three dimensions and the time offset in the receiver clock. GPS devices first became popular during the Persian Gulf War, as they were used extensively by servicemen to find their location.
Since the late 1990s, cellular phone manufacturers have incorporated location based services into long-range radio frequency communications devices such as cellular telephones. In particular, the combination of GPS and cellular services has ben viewed in the vehicle security industry as a sensible combination in view of the worldwide range of a cellular telephone and the corresponding uncertainty of one's absolute geographic position at any one time. Exemplary uses of a combined cellular telephone/GPS system include the ubiquitous OnStar® system deployed in automobiles by automobile manufacturers such as General Motors and Ford Motor Company.
Unlike the combination of cellular telephone and GPS technologies, a similar combination of short-range radio communications and GPS technologies heretofore has not been developed because the limited physical range of a short-range radio communications system has not resulted in the same difficulties of locating one's absolute geographic position. Rather, typically users of short-range communications systems are aware of their general geographic position, particularly given the purpose of the FRS—to enable communications between individuals in a neighborhood or at a group outing. Furthermore, given the typical market for short-range communications systems by comparison to the more expensive GPS systems, it has not been economically feasible to combine both systems.
Nevertheless, it would be desirable to be able to ascertain one's position relative to a companion party in a private, short distance two-way voice communications session. Importantly, it is not usually realistic to reference the location of a companion party in a private, long range two-way communications session such as a cellular telephone call inasmuch as the range of the cellular telephone at an extreme permits intercontinental conversations. In contrast, in short-range voice communications systems, conversing parties typically must be within short range of one another, at most a few miles. Hence, it would be useful to be able to ascertain the location of a companion party to a private, two-way voice communications session.